The holiday lasts seven days in Israel and eight in the diaspora. The first day (and second day in the diaspora) is a Shabbat-like holiday when work is forbidden, followed by intermediate days called Chol Hamoed. The festival is closed with another Shabbat-like holiday called Shemini Atzeret (two days in the diaspora, where the second day is called Simchat Torah).

The Hebrew word sukkōt is the plural of sukkah, "booth" or "tabernacle", which is a walled structure covered with s'chach (plant material such as overgrowth or palm leaves). The sukkah is intended as a reminiscence of the type of fragile dwellings in which, according to the Torah, the Israelites dwelt during their 40 years of travel in the desert after the Exodus from slavery in Egypt. Throughout the holiday, meals are eaten inside the sukkah and many people sleep there as well. A sukkah is also the name of the temporary dwelling in which agricultural workers would live during harvesting.

On each day of the holiday it is mandatory to perform a waving ceremony with the Four Species.

"On the first day you shall take the product of hadar trees, branches of palm trees, boughs of leafy trees, and willows of the brook" (Lev. 23:40), and "You shall live in booths seven days; all citizens in Israel shall live in booths, in order that future generations may know that I made the Israelite people live in booths when I brought them out of the land of Egypt" (Lev. 23:42-43).

The origins of Sukkot are both historical and agricultural. Historically, Sukkot commemorates the forty-year period during which the children of Israel were wandering in the desert, living in temporary shelters. Agriculturally, Sukkot is a harvest festival and is sometimes referred to as Chag HaAsif (חג האסיף, the "Festival of Ingathering"), as it celebrates the gathering of the harvest.[1][2]

Sukkot is an eight-day holiday, with the first day celebrated as a full festival with special prayer services and holiday meals. The seventh day of Sukkot is called Hoshana Rabbah ("Great Hoshana", referring to the tradition that worshipers in the synagogue walk around the perimeter of the sanctuary during morning services) and has a special observance of its own. Outside Israel, the first and last two days are celebrated as full festivals. The intermediate days are known as Chol HaMoed ("festival weekdays"). According to Halakha, some types of work are forbidden during Chol HaMoed.[3] In Israel many businesses are closed during this time.[4]

Throughout the week of Sukkot, meals are eaten in the sukkah and the males sleep there, although the requirement is waived in case of rain. Every day, a blessing is recited over the Lulav and the Etrog.

The sukkah walls can be constructed of any material (wood, canvas, aluminum siding, sheets). The walls can be free-standing or include the sides of a building or porch. The roof must be of organic material, known as s'chach, such as leafy tree overgrowth, schach mats or palm fronds. It is customary to decorate the interior of the sukkah with hanging decorations. the four species.[5]

Prayers during Sukkot include the reading of the Torah every day, reciting the Mussaf (additional) service after morning prayers, reciting Hallel, and adding special additions to the Amidah and Grace after Meals. In addition, the service includes rituals involving the Four Species. The lulav and etrog are not brought to the synagogue on Shabbat.

On each day of the festival, worshippers walk around the synagogue carrying their Four species while reciting Psalm 118:25 and special prayers known as Hoshanot. This takes place either after the morning's Torah reading or at the end of Mussaf. This ceremony commemorates the willow ceremony at the Temple in Jerusalem, in which willow branches were piled beside the altar with worshipers parading around the altar reciting prayers.

A custom originating with Lurianic Kabbalah is to recite the ushpizin prayer to "invite" one of seven "exalted guests" into the sukkah.[6] These ushpizin (Aramaicאושפיזין 'guests'), represent the seven shepherds of Israel: Abraham, Isaac, Jacob, Moses, Aaron, Joseph and David. According to tradition, each night a different guest enters the sukkah followed by the other six. Each of the ushpizin has a unique lesson which teaches the parallels of the spiritual focus of the day on which they visit.

Decorations hanging from the s'chach (top or "ceiling") on the inside of a sukkah.

The second through seventh days of Sukkot (third through seventh days outside Israel) are called Chol HaMoed (חול המועד - lit. "festival weekdays"). These days are considered by halakha to be more than regular weekdays but less than festival days. In practice, this means that all activities that are needed for the holiday—such as buying and preparing food, cleaning the house in honor of the holiday, or traveling to visit other people's sukkot or on family outings—are permitted by Jewish law. Activities that will interfere with relaxation and enjoyment of the holiday—such as laundering, mending clothes, engaging in labor-intensive activities—are not permitted. Religious Jews typically treat Chol HaMoed as a vacation period, eating nicer than usual meals in their sukkah, entertaining guests, visiting other families in their sukkot, and taking family outings. Many synagogues and Jewish centers also offer events and meals in their sukkot during this time to foster community and goodwill.

On the Shabbat which falls during the week of Sukkot (or in the event when the first day of Sukkot is on Shabbat), the Book of Ecclesiastes is read during morning synagogue services in Israel. (Diaspora communities read it the second Shabbat {eighth day} when the first day of sukkot is on Shabbat. This Book's emphasis on the ephemeralness of life ("Vanity of vanities, all is vanity...") echoes the theme of the sukkah, while its emphasis on death reflects the time of year in which Sukkot occurs (the "autumn" of life). The penultimate verse reinforces the message that adherence to God and His Torah is the only worthwhile pursuit. (Cf. Ecclesiastes 12:13,14.)

In the days of the Temple in Jerusalem, all Israelite, and later Jewish men, women, and children on pilgrimage to Jerusalem for the festival would gather in the Temple courtyard on the first day of Chol HaMoed Sukkot to hear the Jewish king read selections from the Torah. This ceremony, which was mandated in Deuteronomy 31:10-13, was held every seven years, in the year following the Shmita (Sabbatical) year. This ceremony was discontinued after the destruction of the Temple, but it has been revived in Israel on a smaller scale.[7]

During the intermediate days of Sukkot, gatherings of music and dance, known as Simchat Beit HaShoeivah (Celebration of the Place of Water-Drawing), take place. This commemorates the drawing of the water for the water-libation on the Altar, an offering unique to Sukkot, when water was carried up the Jerusalem pilgrim road from the Pool of Siloam to the Temple in Jerusalem.

The seventh day of Sukkot is known as Hoshana Rabbah (Great Supplication). This day is marked by a special synagogue service in which seven circuits are made by worshippers holding their Four Species, reciting Psalm 118:25 with additional prayers. In addition, a bundle of five willow branches is beaten on the ground.

The holiday immediately following Sukkot is known as Shemini Atzeret (lit. "Eighth [Day] of Assembly"). Shemini Atzeret is usually viewed as a separate holiday.[8] In the Diaspora a second additional holiday, Simchat Torah ("Joy of the Torah"), is celebrated. In the Land of Israel, Simchat Torah is celebrated on Shemini Atzeret. On Shemini Atzeret people leave their sukkah and eat their meals inside the house. Outside of Israel, many eat in the sukkah without making the blessing. The sukkah is not used on Simchat Torah.[9]

De Moor has suggested that there are links between Sukkot and the Ugaritic New Year festival, in particular the Ugaritic custom of erecting two rows of huts built of branches on the temple roof as temporary dwelling houses for their gods.[10][11]